On the Welfare Gains of Price Dispersion
比较两种定价机制：一种无价格分散，另一种通过事后需求决定价格产生分散。发现低通胀时，价格分散带来的交易频率增加（广延边际）超过交易量下降（集约边际），使福利更高。
Can price dispersion be associated with higher levels of welfare? To answer we compare two economies that differ only in the way prices are formed. In the first, sellers post a unique price–quantity pair, with no price dispersion. In the second, sellers post a quantity only and let prices be determined ex post by realized demand, resulting in price dispersion. We show that while agents trade lower quantities when prices are dispersed (an intensive margin effect), they also trade more often (an extensive margin effect). At low inflation, the extensive margin dominates making agents better off with price dispersion.